The purpose of this research project is to develop and study mathematical models for certain biological phenomena at the molecular level. Current work has focused on (a) developing new estimates of the rate of recombination and determining their statistical properties, (b) developing models for the evolution of a family of highly repeated interspersed DNA sequences, (c) developing statistical tests of the neutral model using nucleotide sequence data, (d) studing the genealogic process associated with models for the evolution of a transposable element family, (e) analyzing the statistical properties of stratified sampling scheme when certain prior information is known, and (f) studying problems relating to the alignment of DNA sequences.